Generally that means Mid-Tier I guess but more from in relation to the main character and the people he comes across, so you're more important or powerful or knowledgeable or whatever is relevant than all the normal dudes but you're basically never gonna make it. Which manga/anime do you pick to inhabit?!?!?
The ramifications of this choice are of your own choosing
Personally I'd be a krillin-tier pokemon character because like I'd get to follow my dreams and be successful in my field but basically still be a pissant in the grand scheme of things. I might even be a gym leader so I have to have some income or clout or SOMETHING. I'm ok being the very greatest gimmick Ghost-Fighting-Steel specified trainer who uses ballet in my fighting in a small region that doesn't matter if that's what keeps food on the table
But could my pride handle all the defeat and irrelevance????